﻿using System;
using System.Numerics;

class DivideSomeFactorials
{
    static void Main()
    {
        int numberN;
        int numberK;
        BigInteger result = 1;

        Console.WriteLine("Type a number N:");
        bool isFirstNumberValid = int.TryParse(Console.ReadLine(), out numberN);
        Console.WriteLine("Type a number K:");
        bool isSecondNumberValid = int.TryParse(Console.ReadLine(), out numberK);

        if (isFirstNumberValid && isSecondNumberValid)
        {
            for (int i = numberN+1; i <= numberK; i++)
            {

                result = result * i;
            }
            Console.WriteLine("The result is:" + result);
        }
        else
        {
            Console.WriteLine("Your input isn`t OK!!!");
        }
    }
}